THE FLOATING PRINCIPLE 275 Although the floating action of this device was satisfactory, the driving or gripping power was found insufficient to hold the work securely, and it became necessary to replace the spring-pins with square-head set-screws, cup-pointed, the ring being tapped out to receive them. The ring was then allowed to float while these screws were lightly set up on the work after which the clamping screws N were tightened. After this change in construction, the action of the mechanism was much improved, and the driving power was found sufficient. Floating Clamping Ring on Grinding Fixture. — The work A shown in Fig. 10, is a steel casting which is to be ground on the two exterior surfaces. A nose-piece D is screwed to the end of the spindle E and is provided with a hardened and ground locating ring B on which the work locates. The stud C is forced into the nose-piece and is threaded on its outer end to receive a spherical nut F. The collar G is concaved to the same radius as the spherical portion of the nut so that it floats against the end of the work.